APPENDIX IV 191 



6. Conditions essential for the growth of plants : five essential con- 



ditions ; conditions of soil favorable for growth ; meth- 

 ods of soil improvement. 



7. (Optional.) Struggle for existence and its effects: Variation 



among plants ; numbers of seeds produced by plants ; 

 struggle for existence among plants; survival of the 

 fittest. 



8. (Optional.) Improvement of plants by man: artificial selec- 



tion of favorable variations ; artificial crossing of related 

 species ; some of the valuable crops of New York State ; 

 some of the methods of increasing crop production. 



H. PLANTS IN THEIR RELATION TO HUMAN WELFARE. 



1. Some uses of plants to man. 



a. Uses of plants for food. 



b. Uses of plants for flavoring extracts, beverages, and medi- 



cines. 



c. Uses of plants for clothing. 



2. Forests and forest conservation. 1 



a. Definitions. 



(1) A forest means a growth of trees sufficiently dense to 

 form a fairly unbroken canopy of trees. A forest 

 has a population of animals and plants peculiar 

 to itself, a soil of its own making, and a climate 

 different from that of the open country. 

 (2) " Forestry is the preservation of forests by wise use." 

 ROOSEVELT. 



b. Value of forests. 



(1) ^Esthetic value beauty of form and color of forest 



trees. 



(2) Value in affecting drainage. 



(a) By retaining water in the soil through the agency 

 of the roots. 



1 The authors are indebted to Miss Kate B. Hixon, of the Morris 

 High School, New York, N.Y., for the review topics on Forests and 

 Forest Conservation. 



